A Rare Case of Acquired Factor VIII Inhibition in an Elderly Female.

Acquired hemophilia A is a rare condition characterized by the development of autoantibodies against coagulation factor VIII. It often initially presents as serious bleeding in the absence of risk factors and carries high morbidity and mortality if not diagnosed early. Due to its rare nature, data is limited, and guidelines are primarily based on expert opinion. Here we present a case of an elderly patient with severe gastrointestinal bleeding found to have activated partial thromboplastin times, plasma mixing studies, and coagulation factor activity levels consistent with acquired hemophilia A. We hope to bring awareness of this rare disease and promote its consideration in the differential of unexpected bleeding to improve safety outcomes.

Valoctocogene roxaparvovec gene therapy provides durable haemostatic control for up to 7 years for haemophilia A.

INTRODUCTION: Valoctocogene roxaparvovec is an adeno-associated virus vector serotype 5 (AAV5)-mediated gene therapy approved for severe haemophilia A (HA). AIM: To report the safety and efficacy of valoctocogene roxaparvovec 7 years after dosing in a phase 1/2 clinical study (NCT02576795). METHODS: Males ≥18 years with severe HA (factor VIII [FVIII] ≤1 international unit [IU]/dL) who were previously receiving exogenous FVIII and had no history of FVIII inhibitors or anti-AAV5 antibodies received valoctocogene roxaparvovec treatment and were followed for 7 (6 × 1013 vg/kg; n = 7) and 6 (4 × 1013 vg/kg; n = 6) years. RESULTS: In the last year, one participant in each cohort reported treatment-related adverse events (AEs): grade 1 (G1) hepatomegaly (6 × 1013), and G1 splenomegaly and G1 hepatic steatosis (4 × 1013). During all follow-up, mean annualized treated bleeds and exogenous FVIII infusion rates were ≥88% lower than baseline values. At years 7 and 6, mean (median) FVIII activity (chromogenic assay) was 16.2 (10.3) and 6.7 (7.2) IU/dL in the 6 × 1013 (n = 5) and 4 × 1013 (n = 4) cohorts, respectively, corresponding to mild haemophilia. Regression analyses of the last year estimated rate of change in FVIII activity was -0.001 and -0.07 IU/dL/week for the 6 × 1013 and 4 × 1013 cohorts, respectively. Two participants (6 × 1013) resumed prophylaxis in year 7: one after a non-treatment-related G4 serious AE of spontaneous internal carotid artery bleed, and the other to manage bleeds and FVIII activity. CONCLUSIONS: The safety and efficacy of valoctocogene roxaparvovec remain generally consistent with previous reports, with good haemostatic control for most participants. Two participants returned to prophylaxis.

Reconstruction of the historic time course of blood-borne virus contamination of clotting factor concentrates, 1974-1992.

Factor VIII and IX clotting factor concentrates manufactured from pooled plasma have been identified as potent sources of virus infection in persons with hemophilia (PWHs) in the 1970s and 1980s. To investigate the range and diversity of viruses over this period, we analysed 24 clotting factor concentrates for several blood-borne viruses. Nucleic acid was extracted from 14 commercially produced clotting factors and 10 from nonremunerated donors, preserved in lyophilized form (expiry dates: 1974-1992). Clotting factors were tested by commercial and in-house quantitative PCRs for blood-borne viruses hepatitis A, B, C and E viruses (HAV, HBV, HCV, HEV), HIV- types 1/2, parvoviruses B19V and PARV4, and human pegiviruses types 1 and 2 (HPgV-1,-2). HCV and HPgV-1 were the most frequently detected viruses (both 14/24 tested) primarily in commercial clotting factors, with frequently extremely high viral loads in the late 1970s-1985 and a diverse range of HCV genotypes. Detection frequencies sharply declined following introduction of virus inactivation. HIV-1, HBV, and HAV were less frequently detected (3/24, 1/24, and 1/24 respectively); none were positive for HEV. Contrastingly, B19V and PARV4 were detected throughout the study period, even after introduction of dry heat treatment, consistent with ongoing documented transmission to PWHs into the early 1990s. While hemophilia treatment is now largely based on recombinant factor VIII/IX in the UK and elsewhere, the comprehensive screen of historical plasma-derived clotting factors reveals extensive exposure of PWHs to blood-borne viruses throughout 1970s-early 1990s, and the epidemiological and manufacturing parameters that influenced clotting factor contamination.

A Rare Case of Life-Threatening Hemorrhage.

Acquired hemophilia A is a rare but severe autoimmune bleeding disorder that results from autoantibodies against clotting factor VIII (FVIII). Distinguishing acquired hemophilia from other more common causes of bleeding, such as chronic liver disease, disseminated intravascular coagulation, or sepsis-induced coagulopathies, is crucial in guiding the management of life-threatening hemorrhage. This study describes a patient with primary biliary cholangitis who was found to have acquired hemophilia A, a unique cause of life-threatening bleeding that was especially challenging to diagnose and manage with her underlying liver disease. Identifying acquired hemophilia A allowed an avenue of treatment options that would not have otherwise been available.

Exploring the relationship between condition severity and health-related quality of life in people with haemophilia A across Europe: a multivariable analysis of data from the CHESS II study.

BACKGROUND: Haemophilia A (HA; Factor VIII deficiency) is a congenital X-linked bleeding disorder characterized by trauma-related or spontaneous bleeding events, most notably arising within the intraarticular space and resulting in chronic inflammation and degeneration of affected joints. Endogenous clotting factor activity relative to normal levels determines the severity of HA symptoms, as mild (> 5-40%), moderate (1-5%), or severe (< 1%). Within the current environment of rapid evolution in HA management, we seek to understand the interplay of condition severity and health-related quality of life (HRQoL) to characterise and differentiate unmet needs among people with HA (PwHA). METHODS: A generalised linear regression model (GLM) was developed to explore the relationship between HA severity and EQ-5D-5 L index score from adult HA patients sampled in the "Cost of Haemophilia across Europe - a Socioeconomic Survey II" (CHESS II) cross-sectional, retrospective burden of illness study among adults with hereditary haemophilia A or B from eight European countries. HA patients of any severity with no active inhibitors during the 12 months prior to data capture and a completeEQ-5D-5 L response were included. A base GLM model was specified with covariates for demographic and clinical characteristics (age, body mass index, country, employment, HA severity, annual bleeding rate, problem joints, and chronic pain). RESULTS: Of 381 evaluable patients, 221 (58.0%) had severe HA, 96 (25.2%) had moderate HA, and 64 (16.8%) had mild HA. Among the covariates included in the GLM model and after controlling for haemophilia-related outcomes, a significant association was observed between mild HA and higher EQ-5D-5 L index score (average marginal effects, 0.084; p = 0.016) relative to severe HA. Patient country of residence and magnitude of HA-related chronic pain were also associated with significant differences in index scores, with the latter showing a negative relationship with HRQoL outcomes. CONCLUSIONS: Condition severity and chronic pain are significant predictors of HRQoL in PwHA. Durable bleeding protection and effective management of chronic pain have the potential to address unmet treatment needs in this population.

Type 2N von Willebrand disease: Genotype drives different bleeding phenotypes and treatment needs.

BACKGROUND: Von Willebrand disease type 2N (VWD2N) is usually perceived as a mild bleeding disorder that can be treated by desmopressin (DDAVP). However, VWD2N-patients can be compound heterozygous or homozygous for different variants, p.Arg854Gln (R854Q) being the most frequent causative one. There is limited data about the impact of 2N-variants on VWD2N phenotype and DDAVP-response. OBJECTIVES: To describe the phenotype of VWD2N, including DDAVP-response, according to genotype. PATIENTS/METHODS: VWD2N-patients with a complete genotype/phenotype characterization by the French reference center for VWD, including MCMDM-1VWD bleeding score (BS) were eligible to the study. Results of DDAVP-trial were also collected. RESULTS: A total of 123 VWD2N-patients from the French registry were included in this study. Results were stratified according to the presence (R854QPos, n=114) or absence (R854QNeg, n=9) of at least one R854Q-allele. Three R854QPos-subgroups were further individualized: patients homozygous (R854QHmz, n=55), compound heterozygous for R854Q and a null allele (R854Q/3, n=48) or compound heterozygous for R854Q and another 2N variant (R854Q/2N, n=11). FVIII: C levels were significantly lower in R854QNeg- and R854Q/3-patients compared to R854QHmz-ones (p<0.001 and p<0.0001 respectively). R854QNeg-patients were diagnosed earlier due to bleeding symptoms and had a higher BS than R854QPos-patients (p<0.001). In DDAVP-trial, FVIII:C survival was lower in VWD type 2N than in type 1. R854QPos-patients had a heterogeneous DDAVP-response, which was best predicted by baseline FVIII:C level. CONCLUSION: The heterogeneous genetic background of VWD2N drives different bleeding phenotypes and response patterns to DDAVP, underlining the clinical relevance of DDAVP-trial to identify patients potentially eligible to alternative therapeutic options.

Kinetic Modeling for BT200 to Predict the Level of Plasma-Derived Coagulation Factor VIII in Humans.

Lack of Factor VIII (FVIII) concentrates is one of limiting factors for Hemophilia A prophylaxis in resource-limited countries. Rondaptivon pegol (BT200) is a pegylated aptamer and has been shown to elevate the level of von Willebrand Factor (VWF) and FVIII in previous studies. A population pharmacokinetic model for BT200 was built and linked to the kinetic models of VWF and FVIII based on reasonable assumptions. The developed PK/PD model for BT200 described the observed kinetic of BT200, VWF, and FVIII in healthy volunteers and patients with mild-to-moderate hemophilia A from two clinical trials. The developed model was evaluated using an external dataset in patients with severe hemophilia A taking recombinant FVIII products. The developed and evaluated PK/PD model was able to describe and predict concentration-time profiles of BT200, VWF, and FVIII in healthy volunteers and patients with hemophilia A. Concentration-time profiles of FVIII were then predicted following coadministration of plasma-derived FVIII concentrate and BT200 under various dosing scenarios in virtual patients with severe hemophilia A. Plasma-derived products, that contain VWF, are more accessible in low-resource countries as compared to their recombinant counterparts. The predicted time above 1 and 3 IU/dL FVIII in one week was compared between scenarios in the absence and presence of BT200. A combination dose of 6 mg BT200 once weekly plus 10 IU/kg plasma-derived FVIII twice weekly maintained similar coverage to a 30 IU/kg FVIII thrice weekly dose in absence of BT200, representing only 22% of the FVIII dose per week.

Real-World Efficacy and Safety of Plasma-Derived Von Willebrand Factor-Containing Factor VIII Concentrates in Patients With Von Willebrand Disease in Italy.

Plasma-derived von Willebrand factor-containing factor VIII concentrates (pd-VWF/FVIII-C) are the mainstay of treatment in von Willebrand disease (VWD). Real-world data on efficacy and safety of these pd-VWF/FVIII-C are required. To retrospectively evaluate the efficacy and safety of pd-VWF/FVIII-C (Fanhdi® and Alphanate®, Grifols) in clinical practice in Italy. A multicentric, observational, retrospective study at 10 Italian centers was conducted. Eligible patients diagnosed with inherited VWD (ISTH criteria) were treated with either Fanhdi® or Alphanate® for bleeding episodes, prevention of surgical bleeding and secondary long-term prophylaxis (SLTP) according to clinical practice with medical records collected from January 2007 to December 2019. Efficacy/safety of pd-VWF/FVIII-C was assessed according to FDA-agreed objective criteria following regulatory procedures. Fifty-seven patients (M/F: 21/36) were enrolled in the study with the following VWD types: VWD1 (n = 29, 52%), VWD2A (n = 10, 18%), VWD2B (n = 7, 12%), VWD2M (n = 2, 4%), VWD2N (n = 1, 2%), VWD2 unclassified (n = 1, 2%), and VWD3 (n = 7, 12%). These pd-VWF/FVIII-C were used to manage 58 bleeding episodes (n = 24 patients), 100 surgeries (n = 47 patients), and 7 SLTP (n = 6 patients). Global clinical efficacy with these pd-VWF/FVIII-C was reported to be excellent/good in 85% of bleeding episodes, 98% of surgeries, and 100% of SLTP. As far as safety, no adverse-drug-related episodes, immunogenic or thrombotic events were reported. This study confirmed that Fanhdi® and Alphanate® were effective and safe in the management of bleeding episodes, the prevention of bleeding during surgeries and for SLTP in Italian patients with inherited VWD.

Bleeding Mystery Unveiled: A Case of Acquired Hemophilia A in the Shadow of Multiple Myeloma.

This case report is of a 50-year-old woman who had a working diagnosis of von Willebrand disease (vWD) due to a history of bleeding complications and continued to experience recurrent bleeding incidents and hematoma. A workup revealed multiple lytic lesions, and a bone marrow biopsy yielded the diagnosis of multiple myeloma. After stem cell transplantation, the patient's factor VIII levels normalized, supporting acquired factor VIII deficiency due to an autoimmune phenomenon. This case highlights the rare occurrence of acquired factor VIII deficiency secondary to multiple myeloma. It also emphasizes the importance of considering secondary causes in patients with a working diagnosis of vWD and recurrent bleeding incidents.

Anti-mCD20 in combination with α-mCXCL13 monoclonal antibody inhibits anti-FVIII antibody development in hemophilia A mice.

Anti-factor VIII (FVIII) antibody development poses a significant challenge in hemophilia A (HA) patients receiving FVIII protein replacement therapy. There is an urgent need for novel therapeutic strategies to inhibit the production of anti-FVIII inhibitory antibodies (inhibitors) in HA. This study aimed to investigate a combination monoclonal antibody (mAb) therapy targeting CXCL13 and CD20 on the development of anti-FVIII antibodies in a HA murine model, along with the underlying mechanisms involved. Specifically, mAbs targeting mouse CD20 (18B12) with an IgG2a backbone and mouse CXCL13 (2C4) with an IgG1 backbone were synthesized. HA mice with FVIII inhibitors were established, and the results revealed that the combination therapy of anti-mCD20 with α-mCXCL13 significantly suppressed anti-FVIII antibody development and induced FVIII tolerance. Furthermore, this combination therapy led to a marked reduction of peripheral and splenic follicular helper T cells and an enhancement of regulatory T cell induction, along with sustained depletion of bone marrow and splenic plasma cells in HA mice with preexisting FVIII immunity. Thus, the concurrence of blockage of CD20 and neutralization of CXCL13 hold promise as a therapeutic strategy for HA patients with inhibitors.

Factor VIII Levels and ISTH Disseminated Intravascular Coagulation Scores Do Not Distinguish Disseminated Intravascular Coagulation from the Coagulopathy of Liver Disease.

INTRODUCTION: Distinguishing disseminated intravascular coagulation (DIC) from the coagulopathy of liver disease represents a common clinical challenge. Here, we evaluated the utility of two diagnostic tools frequently used to differentiate between these conditions: factor VIII (FVIII) levels and the International Society on Thrombosis and Hemostasis (ISTH) DIC score. METHODS: To this end, we conducted a retrospective chart review of patients with DIC, liver disease, or both. Multiple logistic regression was performed, and receiver operating characteristic curves were generated to calculate the area under curve (AUC) for distinguishing DIC in the setting of liver disease. RESULTS: Among 123 patients with DIC, liver disease, or liver disease plus DIC, FVIII levels did not differ significantly. ISTH scores were lower in patients with DIC than in liver disease with or without DIC. Addition of several laboratory parameters to the ISTH score, including mean platelet volume, FV, FVIII, international normalized ratio, and activated partial thromboplastin time, improved AUC for distinguishing DIC in liver disease from liver disease alone (AUC = 0.76; p < 0.0001). CONCLUSION: We conclude that FVIII levels do not distinguish DIC from liver disease, and ISTH DIC scores are not predictive of DIC in patients with liver disease. Inclusion of additional lab variables within the ISTH DIC score may aid in identifying DIC in patients with liver disease.

Efficacy of a 1:1 ratio VWF/FVIII concentrate in patients with von Willebrand disease.

INTRODUCTION: Patients with von Willebrand disease (VWD) require administration of von Willebrand factor (VWF) concentrates peri-operatively. Concerns about FVIII accumulation after repetitive injections of a 1:1 ratio VWF/FVIII clotting factor concentrate (CFC) led this study to explore the recovery and FVIII accumulation over time. METHODS: This monocentre study examined patients with VWD receiving perioperative 1:1 ratio CFC infusions. CFC dosing was based on body weight and endogenous VWF/FVIII activity. FVIII and VWF activity was monitored at T0 (baseline), T1 (15 min postinfusion), and trough levels at T2-T6 (24-120 h). RESULTS: We included 125 patients, undergoing 125 procedures (63 major surgeries, 62 minor), with a median of two CFC infusions (IQR 1-3). With a mean administered dose of 35.7 IU/kg CFC, recovery rates of FVIII and VWF were 2.6 IU/dL per IU/kg and 2.4 IU/dL per IU/kg, respectively. Mean FVIII levels at T0 were 62 (SD 51.9), T1: 164 (SD 80.4), T2: 155 (SD 62.8), T3: 162 (SD 59.8), T4: 124 (SD 78.4), and T5: 120 (SD 65.3) IU/dL. Mean VWF activity levels at T0 were 29 (SD 25.0), T1: 133 (SD 43.7), T2: 92 (SD 37.2), and T3: 86 (SD 37.5) IU/dL. Subgroup analysis in 47 patients with more than three infusions, showed no accumulation of mean FVIII levels. CONCLUSION: This perioperative study demonstrated excellent FVIII and VWF recovery of a 1:1 ratio VWF product in patients with VWD. Stable FVIII and VWF activity levels were observed after repeated infusions, without accumulation. Most major surgeries required only three CFC infusions.

Inhibitor development according to concentrate after 50 exposure days in severe hemophilia: data from the European HAemophilia Safety Surveillance (EUHASS).

Background: Patients with hemophilia have a life-long risk of developing neutralizing antibodies (inhibitors) against clotting factor concentrates. After the first 50 exposure days (EDs), ie, in previously treated patients (PTPs), data on inhibitor development are limited. Objectives: To report inhibitor development according to factor (F)VIII or FIX concentrate use in PTPs with severe hemophilia A and B. Methods: Inhibitor development in PTPs was collected since 2008 from 97 centers participating in European HAemophilia Safety Surveillance. Per concentrate, inhibitors were reported quarterly and the number of PTPs treated annually. Incidence rates (IRs)/1000 treatment years with 95% CIs were compared between concentrate types (plasma derived FVIII/FIX, standard half-life recombinant FVIII/FIX, and extended half-life recombinant (EHL-rFVIII/IX) concentrates using IR ratios with CI. Medians and IQRs were calculated for inhibitor characteristics. Results: For severe haemophilia A, inhibitor rate was 66/65,200 treatment years, IR 1.00/1000 years (CI 0.80-1.30), occurring at median 13.5 years (2.7-31.5) and 150 EDs (80-773). IR on plasma-derived pdFVIII (IR, 1.13) and standard half-life recombinant FVIII (IR, 1.12) were similar, whereas IR on EHL-rFVIII was lower at 0.13 (incidence rate ratio, 0.12; 95% CI, <0.01-0.70; P < .01).For severe hemophilia B, inhibitor rate was 5/11,160 treatment years and IR was 0.45/1000 years (95% CI, 0.15-1.04), at median 3.7 years (95% CI, 2.1-42.4) and 260 EDs (95% CI, 130 to >1000). Data were insufficient to compare by type of FIX concentrates. Conclusion: Low inhibitor rates were observed for PTPs with severe hemophilia A and B. Data suggested reduced inhibitor development on EHL-rFVIII, but no significant difference between plasma-derived FVIII and standard half-life recombinant FVIII. FIX inhibitor rates were too low for robust statistical analysis.

Asymptomatic COVID-19-Associated Acquired Hemophilia A and Disseminated Intravascular Coagulation From a Bypassing Agent.

Acquired hemophilia A (AHA) is a clotting disorder characterized by the presence of neutralizing antibodies that inhibit factor VIII, resulting in increased bleeding risk. Known etiologies include malignancy, autoimmune conditions, graft-vs-host disease, and more recently coronavirus disease 2019 (COVID-19) infection. In this case report, we describe an 86-year-old female who was found to have AHA incidentally during preoperative workup for meningioma resection. She was subsequently found to have COVID-19 infection which was the likely cause of her development of AHA. She was treated with factor eight inhibitor bypassing agent (FEIBA) and recombinant factor VII (rVII) for a small hematoma on her right arm along with prednisone and cyclophosphamide. She then developed disseminated intravascular coagulation (DIC) initially secondary to FEIBA and subsequently rFVII. DIC resolved after these factor concentrates were withheld. The aim of this case report was to emphasize the importance of monitoring partial thromboplastin time (PTT) in patients with COVID-19 and proceeding with AHA workup if indicated. It is also imperative to know and understand the potentially life-threatening, albeit rare, adverse effects of DIC associated with the administration of factor concentrates, especially in the elderly population and withholding these factor concentrates once DIC is suspected.

High levels of anti-factor VIII immunoglobulin G4 and immunoglobulin G total are associated with immune tolerance induction failure in people with congenital hemophilia A and high-responding inhibitors.

Background: Immune tolerance induction (ITI) is the treatment of choice to eradicate neutralizing anti-factor (F)VIII alloantibodies (inhibitors) in people with inherited hemophilia A. However, it is not successful in 10% to 40% of the cases. The biological mechanisms and biomarkers associated with ITI outcome are largely unknown. Objectives: The aim of this study was to investigate the association of plasma cytokines (interferon-γ, tumor necrosis factor, interleukin [IL]-2, IL-4, IL-5, IL-6, IL-10, and IL-17A), chemokines (IL-8/CXCL8, RANTES/CCL5, MIG/CXCL9, MCP-1/CCL2, and IP-10/CXCL10), and anti-FVIII immunoglobulin (Ig) G total, IgG1, and IgG4 with ITI outcome. Methods: In this cross-sectional analysis of the Brazilian Immune Tolerance Study, we assessed plasma levels of anti-FVIII IgGs using an enzyme-linked immunosorbent assay with plasma-derived FVIII and recombinant FVIII as target antigens, immobilized in microplates. Results: We assayed 98 plasma samples of moderately severe and severe (FVIII activity, <2%) people with hemophilia A after completion of a first ITI course. Levels of anti-recombinant FVIII IgG total and IgG4 were higher in people with hemophilia A who failed ITI (IgG total optical density [OD], 0.37; IQR, 0.15-0.73; IgG4 OD, 2.19; IQR, 0.80-2.52) than in those who had partial (IgG total OD, 0.03; IQR, 0.00-0.14; IgG4 OD, 0.39; IQR, 0.09-1.11; P < .0001 for both) or complete success (IgG total OD, 0.04; IQR, 0.00-0.07; IgG4 OD, 0.07; IQR, 0.06-0.40; P < .0001 for both). Plasma cytokines, chemokines, and anti-FVIII IgG1 were not associated with ITI outcome. Conclusion: Our results show that high levels of plasma anti-FVIII IgG4 and IgG total are associated with ITI failure.

Exposure-Response Relationship between VWF/FVIII Activity and Spontaneous Bleeding Events Following Recombinant VWF Prophylaxis in Severe VWD.

Background Recombinant von Willebrand factor (rVWF, vonicog alfa, Takeda Pharmaceuticals USA) is indicated in adults diagnosed with von Willebrand disease (VWD). In this study, the exposure-response (ER) relationship between VWF activity (VWF:RCo) or factor VIII activity (FVIII:C) and spontaneous bleeding events (BEs) was evaluated in adults with severe VWD receiving rVWF prophylaxis for up to 1 year. Methods This secondary analysis included 23 patients receiving rVWF prophylaxis in the open-label, phase 3 prophylaxis trial (NCT02973087). Population pharmacokinetic (PK) and PK/pharmacodynamic (PD) models were used to characterize VWF activity and endogenous FVIII:C, and PK/PD simulations were linked to spontaneous BEs to develop an ER model. Results None of the five patients with VWD types 1 or 2A/B experienced spontaneous BEs. Five of 18 patients with VWD type 3 experienced ≥1 spontaneous BEs. An ER relationship was observed whereby higher VWF:RCo levels were associated with a numerically lower spontaneous BE risk ( p < 0.10). This relationship was independent of patients' pretrial VWF treatment. A statistically significant ER relationship was observed after accounting for relevant data (average ± standard error exposure estimate for VWF:RCo over 24 hours prior to the spontaneous BE: -0.043 ± 0.021, p = 0.041). The model-generated hazard ratio for a 10 IU/dL increment in the average exposure of VWF:RCo 24 hours before a spontaneous BE was 0.651 (95% confidence interval: 0.431-0.982). Conclusions This ER analysis suggests a causal association between VWF:RCo and spontaneous BEs, with an increase of VWF:RCo exposure leading to a decrease in spontaneous BE risk.

Acquired haemophilia A in Finland: A nationwide study of incidence, treatment and outcomes.

INTRODUCTION: Acquired haemophilia A (AHA) is a bleeding disorder caused by autoantibody development against factor VIII (FVIII). Studies on AHA have mainly focused on patients treated at specialist centres. AIM: To determine the incidence, clinical characteristics and outcomes of AHA in an unselected population-based patient cohort from Finland. METHODS: This retrospective observational cohort comprised all cases diagnosed with AHA in Finland between 2006 and 2019. Patients were identified by the two central laboratories performing FVIII antibody testing in Finland, the Finnish Red Cross Blood Service and HUSLAB. Clinical details were collected from all hospitals and healthcare units where patients were treated. This study was performed in conjunction with the AHA in the Nordics study. RESULTS: The median incidence of AHA was 0.65 per million per year (range 0.19-1.27). Fifty-five patients were identified, with a median age of 76 years and an even sex ratio (51% women). When diagnosed, all had bleeding symptoms with severe bleeds in 92%. First-line immunosuppressive treatment regimens included steroid monotherapy in 31% of cases, steroids and a cytotoxic agent in 51% and a rituximab-based regimen in 16%. Clinical remission was achieved in 71% of cases, and 15% had relapses. Mortality was 13% for bleeds and 9% for treatment-related infections. Overall survival was 64% for 1 year and 56% for 2 years after diagnosis. CONCLUSIONS: In a nationwide population-based cohort study, we discovered a lower incidence of AHA than previously reported. Mortality among patients with AHA was high, calling for the consideration of updated treatment strategies.

Physical Activity, Bleedings and Quality of Life in Subjects with Haemophilia A without Inhibitors-A Multicenter, Observational Italian Study with a Wearable Device.

Background: This study aimed to gather data on physical activity (PA), bleeding, health-related quality of life, and health status, using a wearable device and an electronic patient-reported outcome (ePRO) app, in individuals with moderate or severe hemophilia A (HA) without inhibitors receiving treatment according to the clinical practice. Methods: This is a 12-month multicenter cohort study conducted in Italy. The primary outcomes included the description of PA by type and intensity, adherence to World Health Organization guidelines, bleeding, and health-related quality of life by EQ-5D questionnaire. PA data were collected continuously through a fitness tracker worn by the patient; all the other variables were collected through ePRO questionnaires. Results: Only 54 of the 103 enrolled subjects (52.4%) used their fitness tracker for the defined valid period; adolescents were the least compliant age group. PA was performed at low rates and intensity. Approximately 52% of the subjects had sedentary behavior. The mean EQ-5D values did not change over time. At least one bleeding was reported in 43.7% of the subjects, mostly with sedentary behavior. The PA in the 2 days preceding the bleeding was comparable to the one observed in the overall observational period. Conclusions: The systematic recording of data through a fitness tracker and ePRO app shows that subjects with HA without inhibitors have lower-than-expected PA and that they still experience issues related to bleeding.

A rare cause of abdominal pain in pregnancy - mesenteric artery thrombosis and miscarriage in a 34-year-old patient.

BACKGROUND: Mesenteric arterial thrombosis is an extremely rare thrombotic event, especially during pregnancy, that can cause rapid fatal consequences unless the patient receives early definitive treatment. CASE PRESENTATION: We report the case of a 34-year-old female presenting in her seventh week of gestation with severe abdominal pain who was promptly diagnosed with mesenteric artery occlusion amidst incipient miscarriage. The patient underwent a successful mesentery artery embolectomy, recovered and was later diagnosed with elevated factor VIII activity. CONCLUSION: The diagnosis of mesenteric ischemia should be considered in pregnant women presenting with severe abdominal pain and any prior predisposing factors. Our case highlights the pivotal role of the emergency physician in maintaining a high index of suspicion coupled with timely and determined action. The prognosis of this high mortality condition depends on prompt diagnosis, early definite management and successful multidisciplinary cooperation.

Structural basis for inhibition of coagulation factor VIII reveals a shared antigenic hotspot on the C1 domain.

BACKGROUND: Hemophilia A arises from dysfunctional or deficient coagulation factor (F)VIII and leads to inefficient fibrin clot formation and uncontrolled bleeding events. The development of antibody inhibitors is a clinical complication in hemophilia A patients receiving FVIII replacement therapy. LE2E9 is an anti-C1 domain inhibitor previously isolated from a mild/moderate hemophilia A patient and disrupts FVIII interactions with von Willebrand factor and FIXa, though the intermolecular contacts that underpin LE2E9-mediated FVIII neutralization are undefined. OBJECTIVES: To determine the structure of the complex between FVIII and LE2E9 and characterize its mechanism of inhibition. METHODS: FVIII was bound to the antigen binding fragment (Fab) of NB2E9, a recombinant construct of LE2E9, and its structure was determined by cryogenic electron microscopy. RESULTS: This report communicates the 3.46 Å structure of FVIII bound to NB2E9, with its epitope comprising FVIII residues S2040 to Y2043, K2065 to W2070, and R2150 to H2155. Structural analysis reveals that the LE2E9 epitope overlaps with portions of the epitope for 2A9, a murine-derived inhibitor, suggesting that these residues represent a shared antigenic region on the C1 domain between FVIII-/- mice and hemophilia A patients. Furthermore, the FVIII:NB2E9 structure elucidates the orientation of the LE2E9 glycan, illustrating how the glycan sterically blocks interactions between the FVIII C1 domain and the von Willebrand factor D' domain. A putative model of the FVIIIa:FIXa complex suggests potential clashing between the NB2E9 glycan and FIXa light chain. CONCLUSION: These results describe an antigenic "hotspot" on the FVIII C1 domain and provide a structural basis for engineering FVIII replacement therapeutics with reduced antigenicity.